Because of corrosion and sometimes salt deposits in evaporative coolers of the type which evaporate water into a stream of air, it is desirable to eliminate use of metal fastenings in a cooler case. Furthermore, elimination of metal fastenings reduces assembly time and also improves appearance.
In U.S. Pat. No. 3,941,271, Zarges and Zarges, there was disclosed an improvement in receptacles, and in one embodiment a receptacle side wall was provided with a hinge bolt at its lower edge, the ends of which were vertically movable in end slots in a base frame. An outwardly facing projection of the side wall rested on an inwardly directed projection of the base wall when the side wall was erected, but the side wall could be lifted and hinged inwardly. While such an arrangement was suitable for quick assembly (for example on an assembly line), the configuration was not suitable for an evaporative cooler case because of the width restrictions imposed on the side walls by the inwardly directed projections, and it is not apparent how contiguous vertical edges of side, front and rear walls could interengage.
In U.S. Pat. No. 3,917,757 Hoag there was disclosed a construction wherein contiguous vertical edges of side, front and rear walls interengaged with latch means, but screw threaded fasteners were utilised to secure the top wall, and because of this assembly line operations would necessarily be slowed down. The main object of this invention is to provide improvements whereby assembly of the cooler case can be effected by simple hinging and "snap together" operations of side, front, rear and top walls.